Wireless technologies such as Wi-Fi allow electronic devices to exchange data wirelessly (using radio waves) over a computer network and is commonly used to provide high-speed Internet connections to local devices. Commercial organizations such as retail establishments often offer free Wi-Fi as an incentive for a customer to purchase goods. The central problem is how to only offer that Wi-Fi access to customers and not to anyone who can receive the Wi-Fi signal, for example people who are outside of the retail premises in the street. Existing solutions to this problem include keeping the access details secret until requested or displaying them inside the premises. The first solution has the problem that the access details require changing on a regular basis and staff must be kept informed as to the details of the new credentials. The second solution has the problem that the access details are still visible to non-customers.